Ewe Hoggets Research Articles

Hill country sheep production

Data from straightbred Romney and Border Leicester x Romney ewe hoggets, born in the years 1965 to 1967, were used to describe hogget oestrous behaviour, ovulation rate, and live weight. The hoggets were grazed from birth at the Whatawhata Hill Country Research Station. Oestrous activity extended from late March until late July, with a peak from mid May to mid June. The proportion of hoggets exhibiting oestrus in two Romney and in first-, second-, and third-cross Border Leicester X Romney flocks was 52, 64, 76, 76, and 62% respectively in single-, and 50, 50, 60, 61, and 59% in twin-reared hoggets. Differences were found in live weights and weight gains after weaning between those hoggets which did and those which did not exhibit oestrus. In April the former were 3.9 kg heavier if born as singles and 3.0 kg heavier if twins. Classification of hoggets by the time period of first oestrus showed large differences in live weights, those which exhibited oestrus earlier being heavier at weaning, and su...

Compensatory growth and reproductive performance in young sheep given differential nutrition from 9 to 13 months of age

Abstract When Romney ewe hoggets were fed at three levels of winter nutrition and subsequently fed at two levels during spring-summer, between 60 and 133% of the winter weight differences were recovered during spring-summer. Regression analysis showed that 83% of the variation in the twinning rate at first lambing was accounted for by live weight at mating. Every 10 kg increase in mating weight was associated with a 16% increase in twinning rate. Level of winter feeding at the hogget stage had no effect on reproductive performance at first lambing, but spring-summer nutrition was of great importance in determining mating weight and hence the proportion of twins born. The high-plane winter feeding of Romney hoggets is not justified, providing feed is not limiting during the following spring and summer.

Hill country sheep production

Abstract Data from 5,585 straightbred Romney and Border Leicester × Romney lambs and 1,140 ewe hoggets over the period 1959 to 1967 have been used to study the effects of “breed” of flock, age-of-dam, sex, birth-rearing rank, and year-to-year variation on lamb and hogget fleece weights and live weights. The sheep were from six groups: a Romney control (RCR) flock, a Romney flock in which ewes were mated either to Romney (RER) or to Border Leicester rams (REB), and flocks of first-cross (F1), second-cross (F2 ) , and third-cross (F3) Border Leicester X Romney ewes mated to first-cross Border Leicester × Romney rams. The animals were grazed together from birth at the Whatawhata Hill Country Research Station. There was a marked increase in weaning weight from the RCR (44.5 lb) to Fl (49.1 lb), a fall to the F2 (47.0 lb) , and then a further decline with continued interbreeding to the F3 (45.0 lb) and F4 (44.5 lb ) lambs. A similar trend was evident for lamb fleece weights. An increase of 1.3 Ib in fleece weight and 13.1 lb in October live weight was found between the RCR and Fl ewe hoggets, and a decline to the F3, which were 5.5 lb heavier and produced 0.3 lb more wool than the RCR. Correction factors for birth-rearing rank, sex of lamb, and dam age are tabulated for each flock. Fleece weights were, overall, 0.61 lb higher for single- than for twin-born and reared lambs, 0.34 lb higher for twin-singles than for twins, and increased from 2-year-old to 4- and 5-year-old dams. There was little difference in lamb fleece weights between wether and ewe lambs. Weaning weight correction factors for birth-rearing rank were higher for crossbred than for Romney lambs, and those for sex were slightly lower for crossbreds. Overall, weaning weights were 1.6, 2.8, and 3.1 lb higher for 3-, 4-, and 5-year-old dams respectively than for 2-year-olds, and the regression of weaning weight on age was 0.29 lb/day. Age of dam did not markedly affect ewe hogget fleece weight, but single and twin-reared hoggets differed, overall, by 0.4 lb. Correction factors derived for hogget live weight (420 days of age) were lower for age of dam and for birth-rearing rank than were those at weaning. The overall regression of weight on age was 0.23 lb/day,

Fensulfothion

Abstract The acute oral LD50 of both fensulfothion and fensulfothion sulphone was between 6 and 10 mg active ingredient (a.i.)/kg body weight for male rats and between 2 and 3 mg a.i./kg body weight for female rats. For ewe hoggets, the acute oral LD50 of fensulfothion was between 3 and 4 mg a.i./kg body weight. Administration of fcnsulfothion daily at dose rates of 3, 2, I, and 0.5 mg a.i./kg body weight caused death in 2, 4,7, and 13 days respectively. Of 3 other ewe hoggets drenched daily for 20 days at the rate of 0.5 mg a.i./kg body weight, one died, one became moribund, and one survived. No residues of fensulfothion or its oxidation products were detected in samples of fat, muscle, and liver from the latter 3 sheep. In a replicated plot trial pasture was topdressed with pellets of 5% fensulfothion at rates of I Ib and 2 Ib a.i./acre. After 4 weeks the pastures contained residues of 0.4 and 1.0 parts per million fensulfothion respectively. In a second trial, pasture topdressed at the rate of 2 Ib a.i./acre contained 1.1 parts per million fensulfothion after 4 weeks.

Induction of oestrus and ovulation in Romney ewe hoggets with a progestagen

Abstract Ninety-six Romney ewe hoggets from a group of 236 hoggets of known history were treated with intra-vaginal sponges containing 20 mg or 60 mg methyl-acetoxy-progesterone (MAP) for 14 days near the onset of the breeding season. Observations were made for oestrus in all hoggets and for ovulations in a sample of animals from each group. After treatment the amount of MAP “absorbed” from each sponge was chemically determined. The effects of sire, birth rank of hoggets, dose level of MAP, and occurrence of oestrus on the amount of MAP “absorbed” were estimated. The incidence of oestrus within seven days of sponge withdrawal was 62%, and its occurrence was similar for both dose levels of MAP. The numbers of ovulations in treated hoggets were normal.

Increased live weight gain and wool weight from anthelmintic drenching of ewe hoggets in South Canterbury

Abstract Over a period of five years the production responses obtained from drenching young sheep with thiabendazole were examined in 14 trials covering eight localities in South Canterbury. In the first four trials three drenches given at monthly intervals between January and June produced responses ranging from 1.6 lb to 12.6 lb live weight gain and 0.2 lb to 1.6 lb increase in greasy fleece weight. Over the remaining 10 trials drenching at monthly intervals from December or January until August or September increased mean live weight gain by 13.3 lb (range 6.3 lb to 18.6 lb) and mean greasy fleece weight by 1.3 lb (range 0.9 lb to 2.4 lb) compared with undrenched controls. The results also indicated that four drenches, given in January, March, May, and July, could achieve responses averaging 74% of the live weight gain and 79% of the increased greasy wool production from sheep drenched at monthly intervals.

The effect of drenching on the productivity of hoggets

Abstract The effect of fortnightly and of three six-weekly drenches with thiabendazole, from 4 March 1965, on the growth rate, wool production, and faecal egg counts of Romney and Border-Leicester crossbred ewe hoggets, is described. Drenching of Romney hoggets increased liveweight and greasy fleece weight by 7.01b and 0.71b respectively over a 33-week period. Fortnightly drenching increased final liveweight by 1.51b, and greasy fleece weight by 0.3 lb, compared with drenching at three six-weekly intervals.

The measurement of the flow of food to the duodenum of sheep

1. A comparison of the performance of Scottish Blackface ewe hoggets with and without an exteriorised flow to the duodenum was carried out while the animals were fed on hay with a low nitrogen content and added salt. No evidence was found from the food and water consumed, from the weight changes or from a comparison of the organic matter, nitrogen and ash contents of the food and the faeces that the operation caused any permanent disturbance to digestion.2. Regular measurements of the flow of abomasal contents to the duodenum established a pattern of flow that was influenced by feeding. A relationship between the quantities passed per hour from the abomasum and the time devoted to rumination was found, but the relationship appeared to be dissociated in time so that increased rumination preceded the increased passage of contents.3. The mean quantity of abomasal contents passed from four animals was 398 ml./hour. According to the quantities of chromium sesquioxide administered by mouth, passed from the abomasum, and excreted in the faeces this value represents not more than 90% and not less than 86% of the flow that can normally be expected.4. The quantities of organic matter that disappear in the stomach were calculated and represent about half or more of the total disappearance in the alimentary tract.5. Substantially more nitrogen left the abomasum than was eaten in the food daily. Of the nitrogen passing to the duodenum the greater part disappeared in the intestines.6. About twice as much ash left the stomach as was present in the food and about two-thirds of the ash entering the duodenum disappeared in the intestines.

Cobalt and copper in the nutrition of sheep (1)

SUMMARYEvidence is provided to prove that the nutritional malady, Coast Disease, which affects sheep de-pastured without change on the shell-sand littoral of South Australia is due solely to the inability of the pastures to provide the quantity of cobalt and copper necessary to fulfil the nutritional requirements of grazing sheep.An experiment started in 1936 in which five evenly matched groups of young cross-bred ewe hoggets were dosed thrice weekly with cobalt, copper, cobalt plus copper, and with cobalt plus copper together with iron, manganese, zinc and nickel is described.